1. Field of the Disclosure
The present disclosure relates to a vibration generating device, and particularly, a vibration generating device mounted on small-sized electronic equipment.
2. Description of the Related Art
In the related art, in electronic equipment such as a controller of a game machine or a cellular phone having a game function, multi-functionality is employed in order to increase realistic sensations to a user playing a game and to enhance usability during the operation. As an example, a vibration generating device is mounted inside electronic equipment, the electronic equipment is vibrated, and thus, tactile stimulus is applied to the person operating the electronic equipment.
In the vibration generating device, vibrations are generated by rotating an eccentric weight attached to a rotation shaft of a motor, and thus, patterns of the vibrations are changed by only changing a rotating speed. Accordingly, research has been conducted to generate various kinds of vibrations. For example, in Japanese Unexamined Patent Application Publication No. 2003-159565, two eccentric weights are attached, and thus, a large vibration and a small vibration can be generated.
FIGS. 11A and 11B are side views showing a vibration generating device of the related art, FIG. 11A is a side view at the time of a normal rotation, and FIG. 11B is a side view at the time of a reverse rotation.
As shown in FIGS. 11A and 11B, a vibration generating device 100 of the related art includes a motor 101, a rotation shaft 102 of the motor 101, a first weight 103, a second weight 104, and a clutch 105. The entire clutch 105 is inserted into the rotation shaft 102, and the clutch is disposed between the first weight 103 and the second weight 104 and transmits or disconnects the rotation of the rotation shaft 102. As shown in FIG. 11A, when the rotation of the rotation shaft 102 is a normal rotation, the first weight 103 and the second weight 104 are rotated normally, and thus, a large vibration is obtained. However, as shown in FIG. 11B, when the rotation of the rotation shaft 102 is in the reverse rotation state, the second weight 104 is not rotated, only the first weight 103 is rotated, and thus, a small vibration is obtained.
However, even when two eccentric weights are attached and the patterns of the vibrations are controlled, the changeable parameters are obtained only by rotating whichever weight or by changing the rotating speed, and thus, the patterns of the vibrations are limited.